After two years of observation by a small army of volunteers, ranging from local farmers to birders and casual observers, a picture is beginning to emerge of the status of the Curlew, Numenius arquata, in the land that once comprised the hunting forest of Braydon. Sightings have been made from Blakehill Farm in the north to south of Brinkworth and from Purton in the east to Braydon Pond in the west.
Under the project management, enthusiasm and knowledge of Jonny Cooper, and his co-operation with other bodies involved in similar projects, like the Wildlife & Wetlands Trust, a body of information is building up, detailing where the Curlew are to be found and giving an opportunity to devise strategies to protect nesting sites and encourage the expansion of this long-lived, site faithful and sadly declining species. That Jonny has persuaded local farmers to sign up to the scheme is probably the most important step in this process.
One of the issues of monitoring birds is that they fly. If you see six Curlew separately on your walk, apart from being very lucky at seeing such a number, it is impossible to tell exactly how many you actually saw. It could be the same bird seen 6 times or 6 individuals. The standard way of identifying an individual bird is to put a ring on it. However, with standard BTO metal rings they are difficult to read in the field, even using good quality binoculars or telescopes or, as happens more and more these days, a dirty great telephoto lens on an ultra-high-definition camera. This means that, apart from catching the bird once to fit the ring, it has to be caught again to read the number and identify it. This obviously restricts the ability to make casual observations of the size of the local population and causes more disturbance to the birds.
To overcome this, the plan going forward, is to put field readable tags on the birds. These are solid plastic yellow flags, with two bold black capital letters on them, which can be easily read using any of the optics mentioned previously. Jonny successfully found a source of funding for the tags, for a walk-in trap and a Curlew decoy.
Prior to the commencement of this year’s breeding season Jonny got permission from a local landowner to pilot this process. Their permission was granted on the condition that the site remains confidential, so there will be no hints or hidden indicators as to where the site is. Having got agreement to proceed, we set up our first trial on the site where we knew at least one Curlew was present. The trap was set, the decoy put in place and a lure of the call of the male Curlew set away. We were surprised to find that a couple of local birds responded to it straight away. However, they did not get close enough to be trapped. A week later we tried again, with the same result. So, on the basis that if you keep doing the same thing and getting the same result, you need to change something, we changed.
The next time we started later, as dusk was approaching, and actually set three large mesh nets around the trap, on the basis that if one method isn’t successful the other might be. This was the set up:
The decoy was placed in the middle of the trap, together with a lure, and a second lure was placed at the junction of the two 12 metre nets. We sat down about 250 metres from the net and waited. It wasn’t long until we had some Curlew activity: a couple of birds flitting and walking around the set up. After 30 minutes we were successful in trapping a bird in the 18-metre net. Jonny sprinted to extract the bird and got to within two paces when it managed to extricate itself and get away. Frustrating! After he crawled back to his seat and recovered his breath, we sat and waited some more. As it was getting dark another (or the same) bird hit the net. This time the bird had got into the middle of the net set. It managed to extract itself, as the first had, but because it was inside the open triangle, it immediately flew into one of the other nets, giving Jonny the opportunity to grab it.. This time he could walk back carrying the Curlew in his arms. It was fitted with a dark hood to keep it calm. We did not want to put it into a sack as Curlew are prone to getting leg cramps if their legs are kept constrained so, throughout the processing of the bird, its legs were left free except, for the few seconds it took to fit the various rings.
This is the first record that we can find of a Curlew being ringed in Wiltshire. Jonny did some digging through the records and found one record of a retrapped bird back in 1962, but ringed elsewhere.
We are happy that we have found a technique that will work in the future. It will not be used again now until next Spring, when the Curlew first arrive, and before they have started nesting. We will not do anything to disturb their nesting efforts, so we will be monitoring, but not approaching nests and do not intend to ring the chicks. I say “we” but I really mean “Jonny” as he will be doing the bulk of that work.
*UPDATE* It transpires that the first Curlew ringed in Wiltshire were two chicks ringed by Rob Turner and Tony Rowe at Manor Farm, Coulston on 14th June 1984 (thanks Rob). Equally, the first adult was ringed in 1992 and three chicks ringed in 1997. So this is the second adult ringed in Wiltshire.